diff options
| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2012-07-26 08:53:06 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2012-07-26 16:24:14 +0200 |
| commit | 0f6f281b731d20bfe75c13f85d33f3f05b440222 (patch) | |
| tree | 0f8c23d3fca50dd2830ddc978501cd45a0057f45 /arch/s390/mm | |
| parent | 8143adafd2d00b13f1db96ce06b6bf479e0bfe5b (diff) | |
s390/mm: downgrade page table after fork of a 31 bit process
The downgrade of the 4 level page table created by init_new_context is
currently done only in start_thread31. If a 31 bit process forks the
new mm uses a 4 level page table, including the task size of 2<<42
that goes along with it. This is incorrect as now a 31 bit process
can map memory beyond 2GB. Define arch_dup_mmap to do the downgrade
after fork.
Cc: stable@vger.kernel.org
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
| -rw-r--r-- | arch/s390/mm/mmap.c | 12 | ||||
| -rw-r--r-- | arch/s390/mm/pgtable.c | 5 |
2 files changed, 10 insertions, 7 deletions
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index 573384256c5c..c59a5efa58b1 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -103,9 +103,15 @@ void arch_pick_mmap_layout(struct mm_struct *mm) int s390_mmap_check(unsigned long addr, unsigned long len) { + int rc; + if (!is_compat_task() && - len >= TASK_SIZE && TASK_SIZE < (1UL << 53)) - return crst_table_upgrade(current->mm, 1UL << 53); + len >= TASK_SIZE && TASK_SIZE < (1UL << 53)) { + rc = crst_table_upgrade(current->mm, 1UL << 53); + if (rc) + return rc; + update_mm(current->mm, current); + } return 0; } @@ -125,6 +131,7 @@ s390_get_unmapped_area(struct file *filp, unsigned long addr, rc = crst_table_upgrade(mm, 1UL << 53); if (rc) return (unsigned long) rc; + update_mm(mm, current); area = arch_get_unmapped_area(filp, addr, len, pgoff, flags); } return area; @@ -147,6 +154,7 @@ s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr, rc = crst_table_upgrade(mm, 1UL << 53); if (rc) return (unsigned long) rc; + update_mm(mm, current); area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags); } diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 1cab221077cc..e9ac2d60b7e5 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -85,7 +85,6 @@ repeat: crst_table_free(mm, table); if (mm->context.asce_limit < limit) goto repeat; - update_mm(mm, current); return 0; } @@ -93,9 +92,6 @@ void crst_table_downgrade(struct mm_struct *mm, unsigned long limit) { pgd_t *pgd; - if (mm->context.asce_limit <= limit) - return; - __tlb_flush_mm(mm); while (mm->context.asce_limit > limit) { pgd = mm->pgd; switch (pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) { @@ -118,7 +114,6 @@ void crst_table_downgrade(struct mm_struct *mm, unsigned long limit) mm->task_size = mm->context.asce_limit; crst_table_free(mm, (unsigned long *) pgd); } - update_mm(mm, current); } #endif |